|Ciguatera is the closest I can think of (especially for this:
Bonus points if the characters "settle down" together and discover that this situation they thought was stable is not. Relationships are often high maintenance, even when the partner is not, and it's weird that this doesn't show up in romance stories much.), but that story is really an harsh reality slap on your face, you're advised.
What I like in Trivial Pursuit style. Pick your category: